Reducing valve for rock drills



Aug. 21, 1923.

A. H. TAYLOR REDUCING VALVE FOR ROCK DRILLS Filed July 6, 1920 INVENTOR Patented Aug. 21, 1923.

ALBERT H. TAYLOR, ol ne sworn,runner/invents,ess enon To finennsorL-nenns COMPANY, oFjJEnsnY CITY, nnw'annsnrh COREORATION or nnw JERSEY.

v REDUCING VALVE Eon nooK berets."

- Application filed July 6, 1920. Serial'No. 394374;; 3 V i To all whom it may. concern: K vBe it known that I, ALBERT HMTA'YLOR, -a citizen of theUnited 'States, residin at; 1 .Easton, in the county of Northampton, tate of Pennsylvania, have invented a certain. new and useful Improvement in Reducing- Valves for Rock Drills, of which the follow ing is aspecific'ation. f 7 v his invention relates to reducing valves,

but, more particularly tona reducing valvev "for controlling and regulating the pressure of motive fluid infthe feed cylinder of a rock drill of the hammer type, in which the feed-.5.

ingelement consists of a cylinder and piston for advancing the IIlZlChlIlG' to 1ts 'workii The class ofrock drills known as stopedrills' are an example. of the machines employing such feeding means, and my invention. is,v particularly. adapted to stope drills, al? though itmay be used for other machines.

The maintenance of a substantially fixed pressure in the air feed of a'stope idrill has not fully met the requirements of operation,

for, although it is generally desired to carry apressure in the air feed lower than the.

v supply pressure, still it is desirable that the pressure in the air feed increase-to a* certain extent, but not asmuch as the sup-y ply pressure increases. F'urthermore'if the supply pressure falls there is no, way toproduce a corresponding drop in pressure in; the feed cylinder except as the pressure is.

reduced by the tool advancing into the rook.-

In acertain class of machines the pressure in the feed cylinder has been held at a cer-' tain amount below that in the supply in ac cordance with the setting of a spring. But

- in the case of high supply pressure, a con-- siderahle reduction in pressure in the feed cylinderis needed, while at lower pressures in the supply, it is desirable to have practically the same pressure in the air feed. This type of valve also has the same disadvantage as the previous one mentioned, namely, that a sudden drop in'supply' pressure produces no corresponding drop in the air feed cylinder If the operator observes. that the air feed is too strong, he releases the spring pressure on the valve. But the air in the air" feed is trappedv and the de-- sired reduction in pressure does not follow in which case the operator continues to re-"v duce the spring tension. Finally, When the ressure' in the air feed has beenreduced By leakage, orby the tool advancing to its 1mm; the operator finds-that he -has reduced the spring pressure fa'rflbelow' that-required and he must again {adjust the springtosuit mentionechfor maintaining a substantially Anothertrouble withfboth the designs i mentioned; isthe fact that it is almost im possible togmake either type of. valve 1 air tight and as therequirementsof theaair feed'rcpresent a comparatively smallvolume,

especially when drilling-thehard rock, the, vslight leakage past thevalve more-than equals the advance made by the-piston the feed cylinder, tl e result being that the, pres sure in the feed cylinder isgenerally very close to-jthat in the supply; regardless ofhow the springisset 1 1 7 Still another means'of ,maintainingLa reduced pressure iny the feed ,1 cylinder is to provide a constantly open port fromjthe feed cylinderte the atmosphere and vary the-size oft-the openingby'making the 'supply with the feed cylinder under the control oftheoperator.* This has the disadvantage ofbeing very wasteful of motlvefluid owing tot-hefact that aleakage'port "large enough to meet all requirements is open'at alltimes.

The conditions mentioned in the last para- .grap-h have also been reversed and ,al constant supplyto the air feed has been maintained whilethe size of-theleakage port to the atmosphere is adjusted "by theo'perator. Thisis also very wasteful of motive fluid as the supply port must be large enough ;to

takeflcare of all conditions, such as a leaky piston wand;is.thereforemuch in-excess of that normally required, with the result that the excess is allowed-to escape.

l The primary objects of-the-prese-ntinven- -tionare toovercoine the difiicultie's and dis advantages presentin the types ,ofre'ducing V valvesheretofore used .for controlling and the initial; position ofathe valve, and by turning. the valve, the supply isx'g'radually diminished until reduced to only a small fraction, of the full-opening. Furtherturning of the valve continues to decrease the supply opening and. at 'the same time, the leak opening orcommunication from the air 1 fully open the. supply is entirely closed. hen the..valve has been turned toits full limit of travel or rotation, the leak port is fully open and the supply is closed.

supply pressure falls.

I am enabled to produce a corresponding drop in pressure in the feed cylinder if the This reduction in pressure is effected "by cutting down the supply port which admits'live air to the air "feed and at the same time opening the port "to vent the pressure from the feed. I obviate the necessity" of spring adjustments and avoid waste of fluid under pressure which issimple in construction, eiiicie-nt in i operation and substantially fully meets all tion.

the requirements of the airfeed in opera- Furthcr objects of the invention will herematter a'ppe:ar*and to all of these endsthe invention consists otcombinations of ele- 't'ully described and claimed in this speciinents, arrangement of parts and features of construction substantial] as hereinafter fication and shown in V the accompanying drawings in which,

' thereto,

Awith relation to the inlet port taken on the I the line 5 line 3'3 of Figure 2,

Figures 4, 4 and 4 show diagrammatically three positions of thevalve withrelatioufto the exhaust'port taken on the line 4 4 ofFigureQ or bleader from the air teed cylinder, and

Figure 5 is a detail view of the valve on 5 of Figure 3. Referring to the drawing a stope drill selected to illustrate the inventionjand' having the hammer cylinder A connected to the cylinder by means of the usual side bolts C. The drill steel D car G provided with the usual rock engaging point H. The throttle J controls the sup- 1 ply of motive fluid for the machine and K represents the handle for the machine adapt ed to be grasped by the operator.

cated between the percussive element represented by the cylinder A, and the air feed Figure 1 shows the bolts 0. The valve chest L or its equivalent could be arranged in :any suitable loca-" tion on the machine but isipreferably built into the machine so that it is not liable to damage or destruction. The valve chest L may either be a separate piece as shown 'oritmaybe 'encased'in the back end portion or head portion E of the cylinder.

The valve chest L as shown in detail in Figure 2, is formed with a transverse tapered val ve hole P for receiving a: tapered plug valve Q having'th'e operating handle R, the ,rotative movement'of the valve being limited by any suitable meansa's the stop pin S.

While at thesame time producing a valve The valvc chest L and the plug valve Q are provided with suitable ports and-passages adapted to fully open the supply to the valveis in one position, rotation of said plug Q gradually decreasing the supply opening untilit approaches a minimum "and jfurther rotation from this point gradually closing the supply entirely and gradually opening the exhaust until'thje same is fully 7 opened. In order to. accomplish this cycle indifferent longitudinally separate sections of the plug valve. In addition, means are also preferably provided for retaining the valve in different desired positions of rotation.

One suitable and prefer-able arrangement of ports and passages; is that'shown in Figair feed element F, and an exhaust port V leads' from the air teed'elementto-the valve 'hole. The plug valve Q is provided with the j the'supply and exhaust ports preferably'lie 'Figure 1 is a side elevation of a stope' drill having my reducing valve applied bore W at one end having a port Xterminatiug in tapered slots'Y in the peripheryof the I p plug so that as the valve is rotated in either provided with the front head B adapted tobe' direction from the full open position indicated in Figure 3, the supply'will gradual The valve plug Q is also providedqwlith a {longitudinal exhaust' passage way 0; open to atmosphere at its outer end and column nicating at its-inner end with a' transverse passage-\vay'b passing through the plug and termiuatiugin tapered slots 0 'in -the periphery of the valve so that as thevialve is rotated in either direction from-the po- 9 sition of Figure' t the exhaust is-gradually My improved reducing valve is preferably seated in a valve chest L adapted to be 10- opened.

parts may be constructed in different ways,

o'ne preferable construction being that shown in Figure 2 in which the inner or large end of the tapered plug is corrugated at d and adapted to cooperate with the corrugations e on the meeting face of a stop member having a squared bore 9 adapted to receive the squared stem h of a screw threaded removable plug j. A spring 70 surrounding the stem 71, is adapted'to be compressed between the plug '7' and the stop member 7" and constantly presses the stop member against the end of the valve plug Q. The stem h is hollow as shown at 0 and communicates with the chamber 79 in the valve chest by means of opening So that with the valve plug Q, in the position shown in Figures 2 and 3 free communication is afforded from the motive fluid supply of the machine through the inlet port T" in the valve chest, to and through the port X and bore WV of the valve plug and from particular reference to Figure 2 and the diagrammatic views, let it .be assumed that the valve i in position as indicated in Figure 2 in which case the supply to the feed element or feed cylinder F is fully open through the admission port Uas indicated in Figure 3, while the exhaust port V is fully closed. Rotation of the valve plug Q,

clockwise for instance as the diagrammatic figures are viewed will bring the valve to an intermediate position, in which the inlet port T has been gradually closed but is still partially open as indicated in Figure 1 3 while the exhaust port V has been partially opened a indicated in Figure l ued rotation of the valve Q, in the same direc- Contintionwill fully close the inlet port T-as indicated in Figure 3, which closure takes 7 place before the exhaust port V is fully open as indicated in Figuret One of the primary features of the present invention resides-in the fact that the supply through the inlet port T is gradually closed to a small x fraction of the full opening as indicated in Figure 3 before the leak'or exhaust port V starts to :open as indicated in Figure 4".

Another important feature of the invention resides in the fact that allthe motive fluid admitted through the valve i led directly intovthe air feed cylinder F and'separate "ports and passages are, provided through which .the desired amount of motive fluid is permitted to escape directly from the :air feed cylinder to theatmosphere. By this} means there is no direct connection from the. supply to the exhaust, but the. motive fluid; must first pass through the air feed cylinder; and waste is prevented, with more efficient regulation and control of the air feed. 1

I claim:

pressure in the air feed element of a rock drill of the hammer type, a valve chest s .7 In a reducing valve controlling the. air f formed witha valve hole for receiving atwo' part plug valve, one part having longitudi nal movement and being spring pressed against the other rotatable part, the meeting face of'the two parts being serrated or toothed, whereby the rotatablepart is retained in different desired positions of rotation, ports and passages in the valve chest. and in the plug valve adapted to. fully-open the supply to the air feed element when the .valve is in one position, rotation of the plug gradually decreasing the supply opening until it approaches a minimum, further rotation from this point gradually closing the Supply entirely and graduallyv opening the exhaust until the same is fully open.

In testimony whereof I have signed this specification.

ALBERT H. TAYLOR. 

